120 
is furthered by the action of lower organisms. The nutriments, 
the elements of which they are composed, occur in sufficient 
quantities in the soil; this point was already discussed by Treus. 
However these elements should be available to the plants in a 
soluble condition, and this requires various analysing processes. 
When Verserx published the analyses of ashes and masses of 
pumice-stone, made by Winckuer, it already appeared from 
these, that nearly all the elements were present, except nitrogen. 
On the beach this element could be disengaged from the dis- 
composing organic matter that was washed ashore. Nitrogen- 
containing acids were brought to the soil in rain-water; more- 
over pe Krovyrr ') afterwards demonstrated the presence of 
nitrogen-binding bacteria in the soil-samples brought back by 
Ernst. A number of minute organisms, algae, bacteria, fungi 
and moulds play their parts in this process, being organisms 
which, like the blue-algae found by Trevs, are extremely sober 
in their requirements of nutriment. In the first place these little 
plants by their growth cause the surface-soil to crumble and 
moulder more easily, and furthermore when they die and decay 
small amounts of organic matter enter the soil, which are trans- 
formed again by other micro-organisms. Eventually such soils 
will sustain a few frugal plants. On the beach the usual littoral 
plants found what was sufficient for them in the way of nutri- 
tion; typical representatives of this formation throve here after 
a short time, and this contributed to enable other plants to 
start living a few years later, a little more in the interior. 
They were mainly ferns, in fact the same kinds as content 
themselves in other places also with dry, slightly weathered 
soils. The beginning therefore was principally the transportation 
of various soil-organisms such as are wont to effect the chemical 
o _ transformation in the earth, which were succeeded first by ferns 
_ and beach-plants, and next after, by grasses that are organized 
a ee live on mrs exposed soils, such as Saccharum spontaneum UL. 
; Sur une in wn, bce aésobe, sant Vr azote libre de Eatmosphire, a 
mperata saneonce Oyx By their agency the amount of __ 
